Abalone is one of the ocean's most radiant gems. Each piece of abalone shell is totally unique, colors and patterns vary from piece to piece, and animal to animal. Abalone shell is dark and dull on the outer layer, but the inside nacre a miraculous display of color. The hypnotically undulating colors display an iridescence comparable to opal. The dark swirl patterns are the result of layers of protein, while the color swirls are the result of light refracted through layers of calcium.